1. Field of the Invention
The present invention relates to an image and sound recording/reproducing apparatus provided with functions for efficiently and accurately compressing and decompressing animations and still pictures, together with sounds (e.g., a subject's voice).
2. Description of Related Art
There are currently various methods for compressing and decompressing data. As one example, international standards have already been established for coding methods for still pictures and animations. As one coding system for still pictures, there is a Joint Photographic Coding Experts Group (JPEG) system (e.g., see newest MPEG textbook, ASCII, pp. 53 to 56), and as one coding system for animation, there is a Moving Picture Experts Group (MPEG) system. In the MPEG system, there are MPEG1 (e.g., see newest MPEG textbook, ASCII, pp. 89 to 93) for storage media such as CD-ROM, and DAT, and MPEG2 (newest MPEG textbook, ASCII, pp. 129 to 131).
According to the aforesaid examples, in a case of compressing a still picture and a sound, when the still picture is compressed by the JPEG system, unlike the MPEG system, there are no particular regulations concerning a set compression process for any accompanying sound (i.e., previously, still pictures typically did not have sound data associated therewith), and therefore, sound may be individually processed with freedom of choice of a sound processing method to be applied. One approach applying a JPEG image compression/decompression process and an ADPCM sound compression/decompression process can be seen in the reference of "Development of Digital Camera DC-1", ITE Technical Report Vol. 19, No. 45, pp. 15-20 (September 1995). Such approach is disadvantageous in that the ADPCM compression/decompression process is not widely distributed/available, thus making use inconvenient for users.